How evolution made our brains lazy
Blame our ancestors for why it's easier to be a couch potato.
- A new study shows that the brain prefers to expend as little energy as possible.
- Putting forth less effort had advantages for our ancestors.
- Being inactive is not beneficial in modern life and needs addressing.
Why is it often so hard to get off the couch and go to the gym? While you can certainly point to your lack of will power for the inaction, you can also blame evolution for this predicament. Your brain prefers to minimize effort because that's how it's been trained to do it for millennia.
Scientists from the University of Geneva (UNIGE) and the University Hospitals of Geneva (HUG) in Switzerland came to this conclusion after studying the neuron activity of people who had the choice of either engaging in physical activity or doing nothing. The researchers found that it takes much more effort for the brain to escape its general tendency to put forth less effort.
This battle in the mind comes courtesy of our ancestors who aimed to do less to increase the likelihood they would survive. Expending unnecessary energy would have made them more vulnerable to predators or environmental factors. Conserving energy was helpful when competing against rivals, fighting, hunting for prey, and searching for food. Living in modern societies does not require this approach, and yet the predilection of our brains to work less persists.
To gain a better understanding, the scientists based their hypothesis on "the physical activity paradox." You've experienced it if you've ever done something like buying a membership to a gym that you attend with less frequency each passing week. This happens when the conflict between your reason-based knowledge (going to the gym is good for my health) runs into the automatic system based on affect, which is, in this case, all the hurt and tiredness you expect to get out of the physical activity. The result is often paralysis—you remain sedentary.
To delve deeper into what is taking place at the neuronal level, the researchers studied the brain activity of 29 people who desired to be more active in their everyday lives but had a hard time doing so. The subjects were made to choose between physical activity or inactivity as the researchers observed their brains using an electroencephalograph (EEG) with 64 electrodes.
The research team was headed by Boris Cheval from the Faculty of Medicine at UNIGE and HUG and Matthieu Boisgontier from Leuven University, Belgium, and the University of British Columbia, Canada.
Cheval explained how the experiment, where subjects controlled an online avatar, was carried out:
We made participants play the "manikin task," which involved steering a dummy towards images representing a physical activity and subsequently moving it away from images portraying sedentary behaviour [...] They were then asked to perform the reverse action.
The scientists looked at how long it took the participants to get near the sedentary image versus avoiding it and found that it took the subjects 32 milliseconds less to move away from the less active image. Cheval called this result "considerable for a task like this." While such an outcome didn't correspond to their theory of the physical activity paradox at first glance, it actually ended up confirming it.
This animation shows the experiment the participants were asked to perform, moving the avatar closer or farther from the image shown.
Credit: UBC Media Relations
It turned out that the reason for why the participants moved their avatar away from images of physical inactivity and towards active pictures more quickly is because avoiding lazy images forced their brains to work harder. That's due to the fact that the participants wanted to engage in physical activity even if they weren't doing so. Choosing more active images was actually easier to do. As such, the EEG scans suggested that their brains were essentially hardwired towards laziness.
Matthieu Boisgontier explained why evolution preferred the easy way out:
Conserving energy has been essential for humans' survival, as it allowed us to be more efficient in searching for food and shelter, competing for sexual partners, and avoiding predators. [...] The failure of public policies to counteract the pandemic of physical inactivity may be due to brain processes that have been developed and reinforced across evolution.
He thinks one big takeaway from the study is that the brain has to work hard to avoid physical activity. The team's research will next focus on whether the brain can be re-trained.
Check out the new study, published in the journal Neuropsychologia, here.
Young people could even end up less anxiety-ridden, thanks to newfound confidence
- The coronavirus pandemic may have a silver lining: It shows how insanely resourceful kids really are.
- Let Grow, a non-profit promoting independence as a critical part of childhood, ran an "Independence Challenge" essay contest for kids. Here are a few of the amazing essays that came in.
- Download Let Grow's free Independence Kit with ideas for kids.
Philosophers like to present their works as if everything before it was wrong. Sometimes, they even say they have ended the need for more philosophy. So, what happens when somebody realizes they were mistaken?
Sometimes philosophers are wrong and admitting that you could be wrong is a big part of being a real philosopher. While most philosophers make minor adjustments to their arguments to correct for mistakes, others make large shifts in their thinking. Here, we have four philosophers who went back on what they said earlier in often radical ways.
New research establishes an unexpected connection.
- A study provides further confirmation that a prolonged lack of sleep can result in early mortality.
- Surprisingly, the direct cause seems to be a buildup of Reactive Oxygen Species in the gut produced by sleeplessness.
- When the buildup is neutralized, a normal lifespan is restored.
We don't have to tell you what it feels like when you don't get enough sleep. A night or two of that can be miserable; long-term sleeplessness is out-and-out debilitating. Though we know from personal experience that we need sleep — our cognitive, metabolic, cardiovascular, and immune functioning depend on it — a lack of it does more than just make you feel like you want to die. It can actually kill you, according to study of rats published in 1989. But why?
A new study answers that question, and in an unexpected way. It appears that the sleeplessness/death connection has nothing to do with the brain or nervous system as many have assumed — it happens in your gut. Equally amazing, the study's authors were able to reverse the ill effects with antioxidants.
The study, from researchers at Harvard Medical School (HMS), is published in the journal Cell.
An unexpected culprit
The new research examines the mechanisms at play in sleep-deprived fruit flies and in mice — long-term sleep-deprivation experiments with humans are considered ethically iffy.
What the scientists found is that death from sleep deprivation is always preceded by a buildup of Reactive Oxygen Species (ROS) in the gut. These are not, as their name implies, living organisms. ROS are reactive molecules that are part of the immune system's response to invading microbes, and recent research suggests they're paradoxically key players in normal cell signal transduction and cell cycling as well. However, having an excess of ROS leads to oxidative stress, which is linked to "macromolecular damage and is implicated in various disease states such as atherosclerosis, diabetes, cancer, neurodegeneration, and aging." To prevent this, cellular defenses typically maintain a balance between ROS production and removal.
"We took an unbiased approach and searched throughout the body for indicators of damage from sleep deprivation," says senior study author Dragana Rogulja, admitting, "We were surprised to find it was the gut that plays a key role in causing death." The accumulation occurred in both sleep-deprived fruit flies and mice.
"Even more surprising," Rogulja recalls, "we found that premature death could be prevented. Each morning, we would all gather around to look at the flies, with disbelief to be honest. What we saw is that every time we could neutralize ROS in the gut, we could rescue the flies." Fruit flies given any of 11 antioxidant compounds — including melatonin, lipoic acid and NAD — that neutralize ROS buildups remained active and lived a normal length of time in spite of sleep deprivation. (The researchers note that these antioxidants did not extend the lifespans of non-sleep deprived control subjects.)
Image source: Tomasz Klejdysz/Shutterstock/Big Think
The study's tests were managed by co-first authors Alexandra Vaccaro and Yosef Kaplan Dor, both research fellows at HMS.
You may wonder how you compel a fruit fly to sleep, or for that matter, how you keep one awake. The researchers ascertained that fruit flies doze off in response to being shaken, and thus were the control subjects induced to snooze in their individual, warmed tubes. Each subject occupied its own 29 °C (84F) tube.
For their sleepless cohort, fruit flies were genetically manipulated to express a heat-sensitive protein in specific neurons. These neurons are known to suppress sleep, and did so — the fruit flies' activity levels, or lack thereof, were tracked using infrared beams.
Starting at Day 10 of sleep deprivation, fruit flies began dying, with all of them dead by Day 20. Control flies lived up to 40 days.
The scientists sought out markers that would indicate cell damage in their sleepless subjects. They saw no difference in brain tissue and elsewhere between the well-rested and sleep-deprived fruit flies, with the exception of one fruit fly.
However, in the guts of sleep-deprived fruit flies was a massive accumulation of ROS, which peaked around Day 10. Says Vaccaro, "We found that sleep-deprived flies were dying at the same pace, every time, and when we looked at markers of cell damage and death, the one tissue that really stood out was the gut." She adds, "I remember when we did the first experiment, you could immediately tell under the microscope that there was a striking difference. That almost never happens in lab research."
The experiments were repeated with mice who were gently kept awake for five days. Again, ROS built up over time in their small and large intestines but nowhere else.
As noted above, the administering of antioxidants alleviated the effect of the ROS buildup. In addition, flies that were modified to overproduce gut antioxidant enzymes were found to be immune to the damaging effects of sleep deprivation.
The research leaves some important questions unanswered. Says Kaplan Dor, "We still don't know why sleep loss causes ROS accumulation in the gut, and why this is lethal." He hypothesizes, "Sleep deprivation could directly affect the gut, but the trigger may also originate in the brain. Similarly, death could be due to damage in the gut or because high levels of ROS have systemic effects, or some combination of these."
The HMS researchers are now investigating the chemical pathways by which sleep-deprivation triggers the ROS buildup, and the means by which the ROS wreak cell havoc.
"We need to understand the biology of how sleep deprivation damages the body so that we can find ways to prevent this harm," says Rogulja.
Referring to the value of this study to humans, she notes,"So many of us are chronically sleep deprived. Even if we know staying up late every night is bad, we still do it. We believe we've identified a central issue that, when eliminated, allows for survival without sleep, at least in fruit flies."
We must rethink the "chemical imbalance" theory of mental health.
- A new review found that withdrawal symptoms from antidepressants and antipsychotics can last for over a year.
- Side effects from SSRIs, SNRIs, and antipsychotics last longer than benzodiazepines like Valium or Prozac.
- The global antidepressant market is expected to reach $28.6 billion this year.